Drop Down List For Schedule

I am an extreme novice with Excel (Other than basic functions).

I am in the military and run Military Police section that I schedule 3 shifts (Days / Swings / Midnight).

I have developed an Excel spreadsheet to keep track of the schedule. I am trying to create a drop down list to select the person who will be working the shift.

The range of the row I am selecting is several columns long.

I would like to add 70+ workers and be able to select the the row of the worker I am assigning to the shift.
If you look at the spreadsheet this may make more sense.

I have lost many nights sleep over this and any help would be appreciated.

Thanks in advance for any help